Auger



(No Model.)

P. A. GLADWIN.

AUGER.

N0.-26.9,406. Patented De0.19,1'882.

WITNEEEES INVENTEIR xw g 42% am UNITED STATES PATENT OFFICE.

PORTER A. GLADWIN, OF BOSTON, MASSACHUSETTS.

AUGER.

SPECIFICATION forming part of Letters Patent No. 269,406, dated December 19, 1882, Application filed April 25, 1882. (no model.)

To all whom it may concern:

Be it known that I, PORTER A. GLADWIN, of Boston, in the county of Suffolk and State of Massachusetts, have invented new and useful Improvements in Expansive Bits, of which the following is a specification.

In the accompanying drawings, in which similar letters of reference indicate like parts, Figure 1 is a perspective view of an expansible bit embodying my invention. Fig. 2is an enlarged front view of the same. Fig.3 is a horizontal section online :10 at, Fig. 2. Fig. 4 is a plan of the under side.

This bit is made in two parts only. The main portion of the bit consists of the shank A, provided with the dovetail groove a, the cutting-lip b, the spur c, and the point d, which is provided with the groove e, (described in Letters Patent numbered 248,854, granted to me November 1, 1881,) extending into the shank at e. The expansion-cutter B fits and moves horizontally in the dovetail groove a, is provided with cuttinglipfand spur g, and has its back 13 serrated or roughened. It is held in any desired position by means of the set-screw h. The vertical parallel serrations upon the back of the expansion-cutter, in connection with the set-screw h, bearing against it from the rear, preve nt any slipping of the outtcr'and make it firm in any position. The extension 0 of the clearing-groove conducts the chip away.

The cohstruction of the bit in few parts and in such simplicity renders it very rigid and reliable, and also renders practicable the application of the clearing-groove 0.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is-

1. In COlllblIlfltlOIIWlth the shank A of an expansible bit, provided with the groove 0!, the expansion-cutter B, having its back B or inner surface serrated or roughened to prevent slipping iu the shank, substantially as set forth.

2. The herein-described expansible bit, consisting of the shank A, provided with the grooved pointd, extension-groove e, and dovetail groove a, the cutter B, having its back or inner side, B, serrated or roughened, and the screw h, all constructed and arranged substantially as and for'the purpose described.

PORTER A. GLADWIN.

Witnesses:

HENRY W.- WILLIAMS, JOSEPH ISHBAUGH. 

